246
FXUS63 KJKL 162109
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
509 PM EDT Tue Jul 16 2024

.KEY MESSAGES...

- Showers and thunderstorms will impact the region through early
  next week.

- A few thunderstorms, mainly through early this evening, will be
  capable of producing strong to damaging wind gusts.

- Some minor flooding of low lying areas will also be possible
  through Wednesday evening, if storms pass repeatedly over the
  same locations.

- A welcomed relief from the heat follows for Thursday through
  early next week, with afternoon high temperatures in the upper
  70s to lower 80s.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 509 PM EDT TUE JUL 16 2024

The latest upper level map features a positively tilted trough
aligned from southeastern Canada through the central Plains.
Cyclonic flow is fanned out across the northern Plains, Midwest,
and portions of the Great Lakes, stemmed from an embedded low
pressure system currently spiraling over southwest Ontario.
Meanwhile, a ridge center remains parked over New Mexico. At the
surface, a cold front is aligned southwest from the eastern Great
Lakes through portions of the Ohio Valley, before becoming more
quasi-stationary through the Midwest and into the southern Plains.
A leftover boundary is also noted from the eastern portion of the
Ohio Valley through northeastern Kentucky, with scattered
convection popping along this boundary. Plenty of heat and
humidity has also been on tap, with heat indices peaking in the
100 to 105 degree range at times this afternoon.

The models are in very good agreement through the short term
regarding the upper level pattern. The trough will shift southeast
with time, occupying the northeastern portion of the CONUS by
early Thursday and spreading 500 mb height falls across the Ohio
and Tennessee valleys Wednesday into Thursday. The surface cold
front will gradually ease southeast, moving through the
Commonwealth Wednesday night. This will result in an uptick in
convection across eastern Kentucky, providing much needed rainfall
to the area.

Mainly scattered convection can be expected through early this
evening, before weaker forcing and the loss of heating likely
results in a relative lull through around midnight. The threat of
strong to damaging wind gusts from any robust storms would mainly
occur through early this evening, given the ample DCAPE of mainly
greater than 1000 J/kg, along with steep low level lapse rates of
8.5-9C/km in place. Model guidance then suggests an uptick in
PoPs towards the I-64 corridor during the overnight and pre-dawn
hours. Most of the CAM guidance shows more beneficial than
detrimental rainfall, with the exception of the FV3, as it had
been pasting the I-64 corridor with significant heavy rainfall in
previous model runs. The 12z run has since backed off on the
footprint of this rainfall, so am more inclined to side with the
majority of the guidance, with a potential of minor flooding
occurring, should storms train over the same locations.
Temperatures will be rather balmy, with lows mainly in the low
70s.

As the cold front approaches Wednesday afternoon, along with
better mid and upper level support, numerous to widespread
showers and thunderstorms are expected. Humidity will continue to
be high; however, all of the cloud cover will keep highs
restricted to the mid and upper 80s, keeping higher heat indices
in check. Convection will gradually diminish from northwest to
southeast Wednesday night with the loss of heating and as the
front eases off to our southeast. Lows will range from the mid to
upper 60s.

.LONG TERM...(Thursday through Tuesday)
Issued at 345 PM EDT TUE JUL 16 2024

The period will begin much cooler than of late, as there is good
agreement in the ensembles and deterministic guidance that mid-level
ridging breaks down. At the surface, the guidance remains some what
uncertain just how far south the cold front gets, but will still be
much cooler and drier to begin the period from Thursday into Friday.
The uncertainty on the front will affect the far southeast the most,
with fairly low PWATs of only around an inch expected in these areas
that could lead to showers and perhaps a few thunderstorm mainly in
the afternoon and early evening Tuesday and Friday. Outside of
that far southeast areas PWATs will be below 1 inch and will lead
to much drier feel on Friday. The highs will top put in the upper
70s and lower 80s each day and this is about 5 degrees below the
climate normals for this time of year.

The ensembles and deterministic models show some height rises as
we move toward the weekend into early next week. However, it looks
meager as we see a mid-level low push toward the Midwest and the
Ohio Valley looks to get stuck in between these features. Given
this we will continue to see slightly below to near normal
temperatures through the weekend into early next week. We will
also be stuck on the periphery of the ridging and this should
open the door for a slightly more active pattern to possibly lead
to a few bouts of showers and thunderstorms through the period.
Even so, storm total QPF from Saturday into Tuesday is still
around a quarter of an inch in the Bluegrass to around and inch
near the Cumberland Valley. The afternoon highs will also remain
in the low to mid 80s as a result of more unsettled pattern and
cloud cover. Not to mention the 850 mb temperatures flat line in
the around 17 celsius range at best through the remainder of the
period. Right now peak area wide chances of rain will be Tuesday
at around 50-70 percent.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 230 PM EDT TUE JUL 16 2024

Generally VFR conditions will prevail through the majority of the
period. Some isolated to scattered convection will be possible
at all terminals through early this evening, before increasing
chances look to become confined more towards the I-64 corridor,
including KSYM. Any direct hit from thunderstorms will bring
temporary MVFR or lower conditions. As a cold front drops
southeast towards the area later tonight into Wednesday, showers
will expand in areal coverage by the pre-dawn hours Wednesday.
Surface winds of 5 to 10 kts out of the southwest to west
southwest will diminish by early this evening.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...GEOGERIAN
LONG TERM...DJ
AVIATION...GEOGERIAN